It is the common practice to utilize a motor operated gas or electric dryer in or about a great number, if not the majority, of homes in the United States. Most of the dryers that are currently in use employ some type of heat producing means in conjunction with a rotary drum whereby the clothes or other articles to be dried can be tumbled in a heated environment to effect rapid drying. Because of the quantities of moisture and lint that are a necessary by-product of the drying operations, the present dryers are equipped with vents which extend from a portion of the dryer apparatus to the outside of the house or building. In this manner, the hot moisture and lint resulting from the dryer operation can be vented or exhausted outside of the building whereby these wastes will not interfere with the environmental conditions within the building.
Usually, a three inch or four inch galvanized steel, aluminum or plastic duct is installed between the dryer vent outlet and the outside wall to lead the moisture and lint products of the drying procedures as directly as possible exteriorly of the building. For this purpose, an opening or hole of suitable size and location is chiseled, drilled or otherwise provided through the building exterior wall and the vent or duct from the dryer is affixed directly to the building opening in a manner to exhaust the moist air and lint from the dryer directly exteriorly of the house. If desired, a hood or shield can be provided on the exterior wall about the opening to thereby protect the wall opening against the entrance of rain water, wind, etc.
While the existing designs and installations have proved entirely adequate and reliable in venting the hot moist air and the lint which results of the drying operations exteriorly from the building, the present construction inherently creates a heating problem by producing a substantially unrestricted and uninsulated opening between the interior of the building and the exterior of the building at the vent opening. Through this unprotected dryer vent opening, a considerable heat loss can be experienced when the dryer is not in operation, a condition which will function to create drafts and cold spots interiorly of the building adjacent to the wall opening. This unprotected opening results in increased costs of heating the residence due to the need to heat up the additional outside air that will enter the building through the unprotected opening. Sometimes the dryer vent opening is protected with a flap or damper to minimize the heat loss at the opening. However, experience has shown that such a damper is subject to clogging or other malfunction due to the lint and other materials present in the dryer effluent.